Guy Norris/LOS ANGLES
GENERAL ELECTRIC and Pratt & Whitney expect to finalise by the end of the month their joint-venture plans for the new -500/600 growth versions of Boeing 747.
The two manufacturers have "-quickly reached agreement on an engine configuration", but have yet to reach an accord over work assignments, manufacturing responsibilities and associated locations, according to a Boeing source. The negotiations are being led by CFM56 programme manager, Bruce Hughes for GE Aircraft Engines and former PW4084 programme manager, Thomas Harper for P&W.
The companies have decided that a P&W president will preside over the 50/50 joint venture if a GE site is chosen for the headquarters, and vice versa if a P&W factory site is selected. The companies have announced that the study is focused on a completely new baseline engine with GE "conceptually looking at the high-pressure [HP] core and P&W conceptually looking at the low-pressure system."
"In general, in each case, we're taking the technology - not the components - of the PW4000 and GE90 and taking the best of both," says Robert Wolfe, president of P&W large commercial engines. It is believed that the two manufacturers have agreed on a wide-chord titanium fan in preference to the GE90's composite unit. The baseline engine is optimised for the 320-374kN (72,000-84,000lb)-thrust range, but will be available in de-rated form for McDonnell Douglas's proposed MD-XX trijet at around 300kN.
Rolls-Royce is also defining its engine in the run-up to a possible launch of the 747-500/600 effort, now termed the 747MD (major derivative) by Boeing. The UK engine company reveals that its current 747MD engine proposal will be virtually common with the Trent 800 but with a scaled-down HP module.
To achieve the 10% better total operating cost target set by Boeing versus the 747-400 model, R-R is opting to tailor the core rather than fall short on performance by up-rating the Trent 700 or de-rating the Trent 800.
"We've got a number of options, but the best could be the Trent 800 with a bit of weight taken out of it and a slightly smaller core," says Trent chief engineer, Mike Terrett.
He continues:"We can take advantage of the current design to get more specific-fuel-consumption advantages by scaling it down, speeding it up and reducing the flow. It's very cost-effective."
Dubai-based carrier Emirates has taken delivery of its first Boeing 777. The Middle Eastern airline has seven of the Trent 800-powered aircraft on order.
Source: Flight International
